Why must a spacecraft orbiting the L2 point periodically fire small thrusters?

Answer

To correct its trajectory and maintain its halo orbit around L2.

The observatory is not fixed but follows a path, requiring small propulsive burns to maintain the specific halo orbit necessary to keep the Sun, Earth, and Moon shielded from its view.

Why must a spacecraft orbiting the L2 point periodically fire small thrusters?

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